This invention relates to a silicone elastomer composition possessing novel crosslinking points, and more particularly to a silicone elastomer composition possessing two or more organic groups included at least five carbon atoms and a carbon carbon double bond bonding to a silicon atom via at least one carbon atom as the crosslinking points thereof.
Conventional silicone elastomer compositions have vinyl groups as their crosslinking groups. A shaped article of silicone elastomer, therefore, can be obtained by blending a vinyl group-containing polyorganosiloxane as a base polymer with an organic peroxide as a vulcanizer and molding the obtained blend, or blending with a polyorganohydrogen siloxane and a platinum compound and molding the obtained blend.
Conventional organic synthetic rubber compositions are vulcanized with sulfur or a sulfur donor. Some of such organic synthetic rubber compositions (such as, for example, EPDM and butyl rubber) are vulcanized with a substituted or unsubstituted alkylphenol resin or with a quinoid.
The conventional silicone elastomer compositions which contain vinyl groups as their crosslinking-point groups, however, cannot be vulcanized by using any of the vulcanizers intended for the conventional organic synthetic rubber compositions.
Therefore, it has been considered that the obtaining of elastomers having outstanding physical properties is quite hard even if these silicone elastomer is mixed with and vulcanized together with natural rubber or organic synthetic rubber.
On the other hand, when an addition reaction type silicone elsastomer is mixed with natural rubber or organic synthetic rubber, a platinum compound used for crosslinking of the silicone elastomer is poisoned and deactivated by such compounds incorporated in the organic synthetic rubber as, for example, sulfur compounds, amino type compounds, phosphor compounds, as well as a small amount of metal compounds such as Pb, Sn, Zn, Bi and Co. Thus, this process has a disadvantage and is poor in actual usage.